I need to collect objects that are all connected through multiple layers of associations, and I don't know who to do so.
I need to get a collection of CustomText based on a string query param.
Basically I need to do a query that will pull a collection of CustomText by name:
#searched_content = params[:search].downcase
#query = CustomText.where("lower(name) like ?", "%#{#searched_content}%")
but then also filters the #query to only search LineItems that have been a part of an approved order. I am using Spree, where Spree::Order has_many Spree::LineItem. Basically, doing something like this (doesn't work at all, but hopefully you'll be able to see what I'm trying to do):
#query = Spree::LineItem.joins(:order).where(spree_orders: {state: "complete"}).joins(:custom_texts).where("lower(name) like ?", "%#{#searched_content}%"))
Models:
class CustomText < ActiveRecord::Base
belongs_to :custom_set, :inverse_of => :custom_texts
end
class CustomSet < ActiveRecord::Base
belongs_to :spree_line_item, :class_name => Spree::LineItem, :foreign_key => :spree_line_item_id
has_may :custom_texts, :dependent => :destroy, :inverse_of => :custom_set
end
class LineItem < ActiveRecord::Base
has_many :custom_texts, :through => :custom_sets
has_many :custom_sets, :dependent => :destroy, :foreign_key => :spree_line_item_id
end
Any help would be very appreciated.
Well, this was just a simple syntax error with one too many end parenthesis at the end...stupid spelling error.
#query = Spree::LineItem.joins(:order).where(spree_orders: {state: "complete"}).joins(:custom_texts).where("lower(name) like ?", "%#{#searched_content}%")
Related
I have these models simplified:
class Game::Champ < ActiveRecord::Base
has_one :contract, :class_name => "Game::ChampTeamContract", :dependent => :destroy
has_one :team, :through => :contract
# Attributes: :avg => integer
end
#
class Game::Team < ActiveRecord::Base
has_many :contracts, :class_name => "Game::ChampTeamContract", :dependent => :destroy
has_many :champs, :through => :contracts
end
#
class Game::ChampTeamContract < ActiveRecord::Base
belongs_to :champ
belongs_to :team
# Attributes: :expired => bool, :under_negotiation => bool
end
#
So what I want to do here is to find all Game::Champs that have no Game::ChampTeamContract whatsoever OR has, but (is not :under_negociation OR is :expired ), sorted by Champ.avg ASC
I am kinda stuck at using two queries, concating the result and sorting it. I wish there were a better way to to it more "Railish"
UPDATE: Just added a constraint about :expired
Try something like:
Game::Champs.
joins("left outer join game_champ_team_contracts on game_champ_team_contracts.champ_id = game_champs.id").
where("game_champ_team_contracts.id is null or (game_champ_team_contracts.state != ? or game_champ_team_contracts.state = ?)", :under_negotiation, :expired).
order("game_champs.avg ASC")
This is a fairly nasty line if left as-is, so if you use this, it needs tidying up. Use scopes or methods to split it up as much as possible!
I just tested with a super simple query:
#bars1 = Bar.where(:something => 1)
#bars2 = Bar.where(:something => 2)
#bars = #bars1 + #bars2
Not sure if it's right, but it works...
I have the usual polymorphic associations for comments:
class Book < ActiveRecord::Base
has_many :comments, :as => :commentable
end
class Article < ActiveRecord::Base
has_many :comments, :as => :commentable
end
class Comment < ActiveRecord::Base
belongs_to :commentable, :polymorphic => true
end
I'd like to be able to define Book.recently_commented, and Article.recently_commented based on the created_at timestamp on the comments. Right now I'm looking at a pretty ugly find_by_SQL query to do this with nested selects. It seems as though there must be a better way to do it in Rails without resorting to SQL.
Any ideas? Thanks.
For what it's worth, here's the SQL:
select * from
(select books.*,comments.created_at as comment_date
from books inner join comments on books.id = comments.commentable_id
where comments.commentable_type='Book' order by comment_date desc) as p
group by id order by null;
Sometimes it's just best to add a field to the object of which you are commenting. Like maybe a commented_at field of datetime type. When a comment is made on an object, simply update that value.
While it is possible to use SQL to do it, The commented_at method may prove to be much more scalable.
Not sure what your method has looked like previously but I'd start with:
class Book < ActiveRecord::Base
def self.recently_commented
self.find(:all,
:include => :comments,
:conditions => ['comments.created_at > ?', 5.minutes.ago])
end
end
This should find all the books that have had a comment created on them in the last 5 minutes. (You might want to add a limit too).
I'd also be tempted to create a base class for this functionality to avoid repeating the code:
class Commentable < ActiveRecord::Base
self.abstract_class = true
has_many :comments, :as => :commentable
def self.recently_commented
self.find(:all,
:include => :comments,
:conditions => ['comments.created_at > ?', Time.now - 5.minutes])
end
end
class Book < Commentable
end
class Article < Commentable
end
Also, you might want to look at using a plugin to achieve this. E.g. acts_as_commentable.
I am putting together a messaging system for a rails app I am working on.
I am building it in a similar fashion to facebook's system, so messages are grouped into threads, etc.
My related models are:
MsgThread - main container of a thread
Message - each message/reply in thread
Recipience - ties to user to define which users should subscribe to this thread
Read - determines whether or not a user has read a specific message
My relationships look like
class User < ActiveRecord::Base
#stuff...
has_many :msg_threads, :foreign_key => 'originator_id' #threads the user has started
has_many :recipiences
has_many :subscribed_threads, :through => :recipiences, :source => :msg_thread #threads the user is subscribed to
end
class MsgThread < ActiveRecord::Base
has_many :messages
has_many :recipiences
belongs_to :originator, :class_name => "User", :foreign_key => "originator_id"
end
class Recipience < ActiveRecord::Base
belongs_to :user
belongs_to :msg_thread
end
class Message < ActiveRecord::Base
belongs_to :msg_thread
belongs_to :author, :class_name => "User", :foreign_key => "author_id"
end
class Read < ActiveRecord::Base
belongs_to :user
belongs_to :message
end
I'd like to create a new selector in the user sort of like:
has_many :updated_threads, :through => :recipiencies, :source => :msg_thread, :conditions => {THREAD CONTAINS MESSAGES WHICH ARE UNREAD (have no 'read' models tying a user to a message)}
I was thinking of either writing a long condition with multiple joins, or possibly writing giving the model an updated_threads method to return this, but I'd like to see if there is an easier way first. Am I able to pass some kind of nested hash into the conditions instead of a string?
Any ideas? Also, if there is something fundamentally wrong with my structure for this functionality let me know! Thanks!!
UPDATE:
While I would still appreciate input on better possibilities if they exist, this is what I have gotten working now:
class User < ActiveRecord::Base
# stuff...
def updated_threads
MsgThread.find_by_sql("
SELECT msg_threads.* FROM msg_threads
INNER JOIN messages ON messages.msg_thread_id = msg_threads.id
INNER JOIN recipiences ON recipiences.msg_thread_id = msg_threads.id
WHERE (SELECT COUNT(*) FROM `reads` WHERE reads.message_id = messages.id AND reads.user_id = #{self.id}) = 0
AND (SELECT COUNT(*) FROM recipiences WHERE recipiences.user_id = #{self.id} AND recipiences.msg_thread_id = msg_threads.id) > 0
")
end
end
Seems to be working fine!
Also to check if a specific thread (and message) are read:
class Message < ActiveRecord::Base
# stuff...
def read?(user_id)
Read.exists?(:user_id => user_id, :message_id => self.id)
end
end
class MsgThread < ActiveRecord::Base
# stuff...
def updated?(user_id)
updated = false
self.messages.each { |m| updated = true if !m.read?(user_id) }
updated
end
end
Any suggestions to improve this?
Add a named_scope to the MsgThread model:
class MsgThread < ActiveRecord::Base
named_scope :unread_threads, lambda { |user|
{
:include => [{:messages=>[:reads]}, recipiencies],
:conditions => ["recipiences.user_id = ? AND reads.message_id IS NULL",
user.id],
:group => "msg_threads.id"
}}
end
Note: Rails uses LEFT OUTER JOIN for :include. Hence the IS NULL check works.
Now you can do the following:
MsgThread.unread_threads(current_user)
Second part can be written as:
class Message
has_many :reads
def read?(usr)
reads.exists?(:user_id => usr.id)
end
end
class MsgThread < ActiveRecord::Base
def updated?(usr)
messages.first(:joins => :reads,
:conditions => ["reads.user_id = ? ", usr.id]
) != nil
end
end
You might want to take a look at Arel, which can help with complex SQL queries. I believe (don't quote me) this is already baked into Rails3.
I am trying to create a model for a ruby on rails project that builds relationships between different words. Think of it as a dictionary where the "Links" between two words shows that they can be used synonymously. My DB looks something like this:
Words
----
id
Links
-----
id
word1_id
word2_id
How do I create a relationship between two words, using the link-table. I've tried to create the model but was not sure how to get the link-table into play:
class Word < ActiveRecord::Base
has_many :synonyms, :class_name => 'Word', :foreign_key => 'word1_id'
end
In general, if your association has suffixes such as 1 and 2, it's not set up properly. Try this for the Word model:
class Word < ActiveRecord::Base
has_many :links, :dependent => :destroy
has_many :synonyms, :through => :links
end
Link model:
class Link < ActiveRecord::Base
belongs_to :word
belongs_to :synonym, :class_name => 'Word'
# Creates the complementary link automatically - this means all synonymous
# relationships are represented in #word.synonyms
def after_save_on_create
if find_complement.nil?
Link.new(:word => synonym, :synonym => word).save
end
end
# Deletes the complementary link automatically.
def after_destroy
if complement = find_complement
complement.destroy
end
end
protected
def find_complement
Link.find(:first, :conditions =>
["word_id = ? and synonym_id = ?", synonym.id, word.id])
end
end
Tables:
Words
----
id
Links
-----
id
word_id
synonym_id
Hmm, this is a tricky one. That is because synonyms can be from either the word1 id or the word2 id or both.
Anyway, when using a Model for the link table, you must use the :through option on the Models that use the Link Table
class Word < ActiveRecord::Base
has_many :links1, :class_name => 'Link', :foreign_key => 'word1_id'
has_many :synonyms1, :through => :links1, :source => :word
has_many :links2, :class_name => 'Link', :foreign_key => 'word2_id'
has_many :synonyms2, :through => :links2, :source => :word
end
That should do it, but now you must check two places to get all the synonyms. I would add a method that joined these, inside class Word.
def synonyms
return synonyms1 || synonyms2
end
||ing the results together will join the arrays and eliminate duplicates between them.
*This code is untested.
Word model:
class Word < ActiveRecord::Base
has_many :links, :dependent => :destroy
has_many :synonyms, :through => :links
def link_to(word)
synonyms << word
word.synonyms << self
end
end
Setting :dependent => :destroy on the has_many :links will remove all the links associated with that word before destroying the word record.
Link Model:
class Link < ActiveRecord::Base
belongs_to :word
belongs_to :synonym, :class_name => "Word"
end
Assuming you're using the latest Rails, you won't have to specify the foreign key for the belongs_to :synonym. If I recall correctly, this was introduced as a standard in Rails 2.
Word table:
name
Link table:
word_id
synonym_id
To link an existing word as a synonym to another word:
word = Word.find_by_name("feline")
word.link_to(Word.find_by_name("cat"))
To create a new word as a synonym to another word:
word = Word.find_by_name("canine")
word.link_to(Word.create(:name => "dog"))
I'd view it from a different angle; since all the words are synonymous, you shouldn't promote any one of them to be the "best". Try something like this:
class Concept < ActiveRecord::Base
has_many :words
end
class Word < ActiveRecord::Base
belongs_to :concept
validates_presence_of :text
validates_uniqueness_of :text, :scope => :concept_id
# A sophisticated association would be better than this.
def synonyms
concept.words - [self]
end
end
Now you can do
word = Word.find_by_text("epiphany")
word.synonyms
Trying to implement Sarah's solution I came across 2 issues:
Firstly, the solution doesn't work when wanting to assign synonyms by doing
word.synonyms << s1 or word.synonyms = [s1,s2]
Also deleting synonyms indirectly doesn't work properly. This is because Rails doesn't trigger the after_save_on_create and after_destroy callbacks when it automatically creates or deletes the Link records. At least not in Rails 2.3.5 where I tried it on.
This can be fixed by using :after_add and :after_remove callbacks in the Word model:
has_many :synonyms, :through => :links,
:after_add => :after_add_synonym,
:after_remove => :after_remove_synonym
Where the callbacks are Sarah's methods, slightly adjusted:
def after_add_synonym synonym
if find_synonym_complement(synonym).nil?
Link.new(:word => synonym, :synonym => self).save
end
end
def after_remove_synonym synonym
if complement = find_synonym_complement(synonym)
complement.destroy
end
end
protected
def find_synonym_complement synonym
Link.find(:first, :conditions => ["word_id = ? and synonym_id = ?", synonym.id, self.id])
end
The second issue of Sarah's solution is that synonyms that other words already have when linked together with a new word are not added to the new word and vice versa.
Here is a small modification that fixes this problem and ensures that all synonyms of a group are always linked to all other synonyms in that group:
def after_add_synonym synonym
for other_synonym in self.synonyms
synonym.synonyms << other_synonym if other_synonym != synonym and !synonym.synonyms.include?(other_synonym)
end
if find_synonym_complement(synonym).nil?
Link.new(:word => synonym, :synonym => self).save
end
end
I have a data model something like this:
# columns include collection_item_id, collection_id, item_id, position, etc
class CollectionItem < ActiveRecord::Base
self.primary_key = 'collection_item_id'
belongs_to :collection
belongs_to :item
end
class Item < ActiveRecord::Base
has_many :collection_items
has_many :collections, :through => :collection_items, :source => :collection
end
class Collection < ActiveRecord::Base
has_many :collection_items, :order => :position
has_many :items, :through => :collection_items, :source => :item, :order => :position
end
An Item can appear in multiple collections and also more than once in the same collection at different positions.
I'm trying to create a helper method that creates a menu containing every item in every collection. I want to use the collection_item_id to keep track of the currently selected item between requests, but I can't access any attributes of the join model via the Item class.
def helper_method( collection_id )
colls = Collection.find :all
colls.each do |coll|
coll.items.each do |item|
# !!! FAILS HERE ( undefined method `collection_item_id' )
do_something_with( item.collection_item_id )
end
end
end
I tried this as well but it also fails with ( undefined method `collection_item' )
do_something_with( item.collection_item.collection_item_id )
Edit: thanks to serioys sam for pointing out that the above is obviously wrong
I have also tried to access other attributes in the join model, like this:
do_something_with( item.position )
and:
do_something_with( item.collection_item.position )
Edit: thanks to serioys sam for pointing out that the above is obviously wrong
but they also fail.
Can anyone advise me how to proceed with this?
Edit: -------------------->
I found from online documentation that using has_and_belongs_to_many will attach the join table attributes to the retreived items, but apparently it is deprecated. I haven't tried it yet.
Currently I am working on amending my Collection model like this:
class Collection < ActiveRecord::Base
has_many :collection_items, :order => :position, :include => :item
...
end
and changing the helper to use coll.collection_items instead of coll.items
Edit: -------------------->
I've changed my helper to work as above and it works fine - (thankyou sam)
It's made a mess of my code - because of other factors not detailed here - but nothing that an hour or two of re-factoring wont sort out.
In your example you have defined in Item model relationship as has_many for collection_items and collections the generated association method is collection_items and collections respectively both of them returns an array so the way you are trying to access here is wrong. this is primarily case of mant to many relationship. just check this Asscociation Documentation for further reference.
do_something_with( item.collection_item_id )
This fails because item does not have a collection_item_id member.
do_something_with( item.collection_item.collection_item_id )
This fails because item does not have a collection_item member.
Remember that the relation between item and collection_items is a has_many. So item has collection_items, not just a single item. Also, each collection has a list of collection items. What you want to do is probably this:
colls = Collection.find :all
colls.each do |coll|
coll.collection_items.each do |collection_item|
do_something_with( collection_item.id )
end
end
A couple of other pieces of advice:
Have you read the documentation for has_many :through in the Rails Guides? It is pretty good.
You shouldn't need the :source parameters in the has_many declarations, since you have named your models and associations in a sensible way.
I found from online documentation that using has_and_belongs_to_many will attach the join table attributes to the retreived items, but apparently it is deprecated. I haven't tried it yet.
I recommend you stick with has_many :through, because has_and_belongs_to_many is more confusing and doesn't offer any real benefits.
I was able to get this working for one of my models:
class Group < ActiveRecord::Base
has_many :users, :through => :memberships, :source => :user do
def with_join
proxy_target.map do |user|
proxy_owner = proxy_owner()
user.metaclass.send(:define_method, :membership) do
memberships.detect {|_| _.group == proxy_owner}
end
user
end
end
end
end
In your case, something like this should work (haven't tested):
class Collection < ActiveRecord::Base
has_many :collection_items, :order => :position
has_many :items, :through => :collection_items, :source => :item, :order => :position do
def with_join
proxy_target.map do |items|
proxy_owner = proxy_owner()
item.metaclass.send(:define_method, :join) do
collection_items.detect {|_| _.collection == proxy_owner}
end
item
end
end
end
end
Now you should be able to access the CollectionItem from an Item as long as you access your items like this (items.with_join):
def helper_method( collection_id )
colls = Collection.find :all
colls.each do |coll|
coll.items.with_join.each do |item|
do_something_with( item.join.collection_item_id )
end
end
end
Here is a more general solution that you can use to add this behavior to any has_many :through association:
http://github.com/TylerRick/has_many_through_with_join_model
class Collection < ActiveRecord::Base
has_many :collection_items, :order => :position
has_many :items, :through => :collection_items, :source => :item, :order => :position, :extend => WithJoinModel
end